Abstract:
This paper selects broadband teleseismic waveform data recorded by the China Digital Seismography Network to study the crustal structure in China.The crustal thickness and
vP/
vS ratio are estimated by the grid-search method.The result shows that the
vP/
vS ratio is between 1.6 and 1.9, and the crustal thickness ranges 29—81 km in China.The gradient belt between 100°E and 110°E divided China into eastern and western parts.The crustal thickness beneath eastern China smoothly ranges from 31 km to 36 km, while the crustal thickness in the western part is relatively thick and changed greatly.Crustal thickness ranges from 34 km to 49 km in the middle of China.In general, the crust in Tibetan Plateau is the thickest, reaching 81 km; crustal thickness decreases in Tianshan, Junggar basin and Inner Mongolia and thins out in South China coastal.The average
vP/
vS ratio over China crust is about 1.738 (
σ=0.253), which is significantly lower than the average 1.78 (
σ=0.269) of global continental crust.The lower
vP/
vS ratio may imply the existence of low velocity zone in the crust or the absence of mafic in China.